I have had the same thing happen on my 8330 Curve. The phone can just be sitting on the table and one minute it will make a noise for a message or call and then after i respond to a message, it wont even make a noise when then next message comes in. Just flashes red up in right hand corner. I have also had the problem of it switching my ring tone from the one i chose to the original one that the phone came with and that's when i know its about to not make any sound at all.

THis is something that is happening to my Blackberry Storm.
I will re-boot, the sounds work, then they quit.
I imagine this is something to do with the profiles, but wonder if anyone else has noticed this lately?

I have same problem. Battery hard reset fixes it. This started happening with over a years use of the phone with no problem. As I run a business, I cannot tolerate the phone going into silent mode randomly. Customer support call suggested the battery reset. But this is recurring and warrants replacement in my opinion.

I have had cell phones for over 15 years now and I have used many different cell phones. This is the most user unfreindly operating system I have ever encountered anything as difficult as this system.
My alarm just decided to quit working one day. Fortunately I awoke on my own. I can see the white screen when it is supposed to go off and then the smooze, but no sound.
y ringer quit working at the same time.
This is unacceptable to me. I can not use this as a business phone and need help!

I noticed this same thing happening to me the other day. The alarm makes no sound but it used to. I also noticed that this is happening at the same time that my camera zoom stopped working. Sounds like there might be a bug where certain parts of the phone just freeze up and stop working.

I have a Bold and my ringer went belly up about three months ago. I gave it to my IT department several times and they could find no reason why it wasn´t ringing. BTW, I did all of the battery pulls, BB wipes, profile checks etc., all to no avail. Luckily it is still under warranty. I just took it to the service provider´s tech repair center. After three days the service center called yesterday and said that there is a design defect, they can´t fix it, they are returning the unit to RIM and I will be recieving a replacement Bold.

__________________
Just trying to get a straight answer in a twisted world.
Torch(Personal) Storm(Personal Backup)and Bold (Work).